I needed new limiters for weights in my roller shades from Rząska brand. Original ones often break and I could not find where to buy replacements. 

This design is not a 1:1 copy, but a good enough replacement. If you have such shades or similar, where internal diameter of the weights is 7 mm, it should fit. Feel free to enhance the model.

I printed it with PLA - not tried other materials yet.